MediaRouteProvider overview

The Android media router framework allows manufacturers to enable playback on their devices
through a standardized interface called a MediaRouteProvider.
A route provider defines a common interface for playing media on a receiver device, making it
possible to play media on your equipment from any Android application that supports media
routes.

Overview

The Android media router framework enables media app developers and media playback device
manufacturers to connect through a common API and common user interface. App developers that
implement a MediaRouter interface can then connect to the
framework and play content to devices that participate in the media router framework. Media
playback device manufacturers can participate in the framework by publishing a MediaRouteProvider that allows other applications to connect to and
play media on the receiver devices. Figure 1 illustrates how an app connects to a receiving
device through the media router framework.

Figure 1. Overview of how media route provider classes provide communication
from a media app to a receiver device.

When you build a media route provider for your receiver device, the provider serves the
following purposes:

Describe and publish the capabilities of the receiver device so other apps can discover it
and use its playback features.

Wrap the programming interface of the receiver device and its communication
transport mechanisms to make the device compatible with the media router framework.

Distribution of route providers

A media route provider is distributed as part of an Android app. Your route provider can be
made available to other apps by extending
MediaRouteProviderService or wrapping your implementation of
MediaRouteProvider with your own service and declaring an intent
filter for the media route provider. These steps allow other apps to discover and make use of
your media route.

Note: The app containing the media route provider can also include a
MediaRouter interface to the
route provider, but this is not required.

Media router library

The media router APIs are defined in the
v7-mediarouter support library.
You must add this library to your app development project.
For more information on adding support libraries to your
project, see Support Library
Setup.

Creating a Provider Service

The media router framework must be able to discover and connect to your media route provider
to allow other applications to use your route. In order to do this, the media router framework
looks for apps that declare a media route provider intent action. When another app wants to
connect to your provider, the framework must be able to invoke and connect to it, so your provider
must be encapsulated in a Service.

The following example code shows the declaration of a media route provider service and the
intent filter in a manifest, which allows it to be discovered and used by the media router
framework:

This manifest example declares a service that wraps the actual media route provider classes.
The Android media router framework provides the
MediaRouteProviderService class for use as a service wrapper for
media route providers. The following example code demonstrates how to use this wrapper
class:

Java

Specifying Route Capabilities

Apps connecting to the media router framework can discover your media route through your
app's manifest declarations, but they also need to know the capabilities of the media routes you
are providing. Media routes can be of different types and have different features, and other apps
need to be able to discover these details to determine if they are compatible with your route.

Route categories

As part of the programmatic description of your media route provider, you must specify
whether your provider supports remote playback, secondary output, or both. These are the route
categories provided by the media router framework:

CATEGORY_LIVE_AUDIO
— Output of audio to a secondary output device, such as a wireless-enabled music system.

CATEGORY_LIVE_VIDEO
— Output of video to a secondary output device, such as Wireless Display devices.

If you specify the CATEGORY_REMOTE_PLAYBACK intent, you must also define what media types and
playback controls are supported by your media route provider. The next section describes how to
specify these settings for your device.

Media types and protocols

A media route provider for a remote playback device must specify the media types and transfer
protocols it supports. You specify these settings using the IntentFilter
class and the addDataScheme() and
addDataType() methods of that object. The
following code snippet demonstrates how to define an intent filter for supporting remote video
playback using http, https, and Real Time Streaming Protocol (RTSP):

Playback controls

A media route provider that offers remote playback must specify the types of media controls
it supports. These are the general types of control that media routes can provide:

Playback controls, such as play, pause, rewind, and fast-forward.

Queuing features, which allow the sending app to add and remove items
from a playlist which is maintained by the receiver device.

Session features, which prevent sending apps from interfering with each
other by having the receiver device provide a session id to the requesting app and then checking
that id with each subsequent playback control request.

The following code example demonstrates how to construct an intent filter for supporting
basic media route playback controls:

For more information about the available playback control intents, see the
MediaControlIntent class.

MediaRouteProviderDescriptor

After defining the capabilities of your media route using IntentFilter objects, you can then create a descriptor object for publishing to
the Android media router framework. This descriptor object contains the specifics of your media
route's capabilities so that other applications can determine how to interact with your media
route.

The following example code demonstrates how to add the previously created intent filters to a
MediaRouteProviderDescriptor and set the descriptor for use by
the media router framework:

Controlling Routes

When an application connects to your media route provider, the provider receives playback
commands through the media router framework sent to your route by other apps. To handle these
requests, you must provide an implementation of a MediaRouteProvider.RouteController class, which processes the commands
and handles the actual communication to your receiver device.

onRelease()
— Called when the route is no longer needed by the framework, allowing it to free its
resources.

All playback control requests, except for volume changes, are directed to the onControlRequest()
method. Your implementation of this method must parse the control requests and respond to them
appropriately. Here is an example implementation of this method which processes commands for a
remote playback media route:

It is important to understand that the MediaRouteProvider.RouteController class is intended to act as a wrapper
for the API to your media playback equipment. The implementation of the methods in this class is
entirely dependent on the programmatic interface provided by your receiving device.